Re: [Qemu-devel] [PATCH v1 4/5] s390x/pci: Refuse to realize VFIO-PCI if AIS needed but supported

From: Pierre Morel <pmorel@linux.vnet.ibm.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	qemu-devel@nongnu.org, borntraeger@de.ibm.com,
	pasic@linux.vnet.ibm.com, zyimin@linux.vnet.ibm.com,
	agraf@suse.de
Subject: Re: [Qemu-devel] [PATCH v1 4/5] s390x/pci: Refuse to realize VFIO-PCI if AIS needed but supported
Date: Thu, 12 Oct 2017 12:12:05 +0200	[thread overview]
Message-ID: <68c3c95e-7f8c-5305-5df4-f512cd5dfb72@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171011142053.1f1e2723.cohuck@redhat.com>

On 11/10/2017 14:20, Cornelia Huck wrote:
> On Tue, 10 Oct 2017 18:01:53 +0200
> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:
> 
>> Since in the case we have no AIS in KVM only PCI is impacted, do you
>> think we can fence IRQFD for MSI with
>>
>> kvm_msi_via_irqfd_allowed = false;
>>
>> in kvm_arch_init_irq_routing() ?
> 
> Hm, it seems we never set that for s390x... does that imply that we
> never support irqfd for pci anyway?
> 
>>
>> In fact, if we also verify the AIS availability in the same routine we
>> can avoid the ugly include of vfio/pci.h
> 
> If we can get the serialization right (and setting that value to false
> does indeed have the desired effect), that's probably the way to go.
> 

OK, thanks, I give it a try and propose a v2 on this basis.

-- 
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany